sabato 24 agosto 2013

No middle ground in fracking debate, by Guy Chazan (FT)

A useful and clear Q&A article to help everyone wants to know more about hydraulic fracking and shale gas. Financial Times (here with Guy Chazan) is trying to consider pros and cons of fracking, presenting both sides of the same coin in a hard-to-find impartial manner.

Enjoy your read.

Balcombe, the leafy West Sussex village where UK shale pioneer Cuadrilla is drilling for oil, is ground zero in an increasingly fiery national debate about fracking, the controversial extraction technique.
On one side is David Cameron, prime minister, who says exploiting the UK’s shale gas reserves will drive down energy bills and make Britain more competitive. On the other are environmentalists who say fracking poisons water supplies, pollutes the atmosphere and triggers earthquakes. Attitudes are hardening, as the two sides dig in. “The problem is there’s no middle ground any more,” says Joseph Dutton of Leicester University’s Global Gas Security Project. “We need an informed, rational debate, not the highly emotional discourse we have right now.”

Exhibit A is Gasland, a 2010 documentary that shows a Colorado man setting his kitchen tap water on fire with a cigarette lighter. Regulators said that was in fact caused by “biogenic” gas that has been detected in local groundwater for years, and had nothing to do with fracking. “There are a lot of misconceptions,” says Susan Brantley, professor of geosciences at Pennsylvania State University. But they have proved enduring, and are even influencing policy, as well as public opinion. France and Bulgaria have banned fracking outright, and green campaigners say the UK should do the same. The FT considers the process and its pros and cons.

What is shale?

Shales are the most abundant form of sedimentary rock. They also serve as the “source rock” for oil and gas that migrates over time into conventional reservoirs, where it can easily be extracted. A lot of hydrocarbons are still in shale, but for decades, geologists could not figure out a way to access them, stymied by the low permeability of the rock. In recent years, that has changed. Oil companies in the US worked out a way of using techniques such as horizontal drilling, hydraulic fracturing, or “fracking”, and 3D seismic imaging to unlock North America’s vast shale resources.

What is fracking?

Fracking involves pumping fluid into a shale formation at high pressure to create cracks in the rock. The fluid contains a “proppant” such as sand which “props” open the fractures: the oil and gas then flows through these pathways towards the well. The fracking fluid is mainly made up of water, but also contains chemical additives such as polymers to reduce friction and allow the water to be pumped at lower pressures.

Is fracking new?

About a million wells have been fracked in the US since the 1940s, when the technique was first used, although pressures used in the process have increased vastly since then. The big change happened in the 1990s when fracking was applied to shale and, combined with horizontal drilling, released enormous quantities of gas that had previously been impossible to extract economically.

What has been the effect?

Shale gas production has soared in the US, providing a wave of cheap and abundant energy. In 2000, shale represented just two per cent of US natural gas supply. By 2012 it was 37 per cent. Last year, the surge in output pushed the US gas price to 10-year lows.

Can it happen here?

The government and Cuadrilla say yes. Latest estimates suggest there are about 1,300tn cubic feet of shale gas in the northwest of England alone. Even if only a tenth of that can be extracted, it is still the equivalent of 51 years’ supply. The government says developing this resource will create jobs, bring down fuel bills and reduce dependence on imported gas. Even the Church of England says fracking could help tackle fuel poverty: “blanket opposition . . . fails to take into account those who suffer most when resources are scarce”, it says.

What are the environmental concerns?

One of the most common objections is that the process can contaminate groundwater. Environmentalists say that methane can leak into aquifers in areas where shale gas drilling has taken place – a fact confirmed in a 2011 study by Duke University. But the industry argues that fractures usually remain separated from groundwater aquifers by thousands of feet of rock, and there is next to no risk of leakage, especially if well casings are structurally sound.
One academic review published in 2011 by the Massachusetts Institute of Technology concluded that the environmental impacts of shale are “challenging but manageable”, and that properly constructed wells should pose no problem. But it did identify some risks, such as surface spills of fracking fluids, pollution from inappropriate wastewater disposal and excessive water withdrawals.
Water use is a key issue. Some 4-6m gallons of water are required to frack each well and in some parts of the US that have been hit by drought, there are concerns about how fracking can affect the availability of water for other purposes, such as agriculture.
Waste water is also a problem. After a well is fracked, some of the fluid comes back up to the surface along with “flowback”, naturally-occurring water from deep underground that can contain pollutants or even radioactivity and requires careful disposal. Regulators are now increasingly calling on companies to reduce waste by recycling more water from fracking operations.

Can fracking cause earthquakes?

Cuadrilla had to suspend operations in the northwest of England in 2011 after its fracking caused a sequence of “seismic events”. But experts say fracking-related earthquakes are relatively rare and, when they do occur, are too small to be detected on the surface. They say coal-mining is much more likely to cause tremors than fracking for gas.
A larger problem is the disposal wells where flowback water from fracking is deposited for permanent storage. A study by researchers at Columbia University says that as many as 109 tremors in Ohio in 2011 and 2012 were directly linked to a well in which wastewater from fracking in nearby Pennsylvania was being injected deep underground.

What about the impact on communities?

Some of the residents of Balcombe are neutral on the fracking process, but do not want to see a big industrial development on the edge of their village. They worry about the impact on local air quality of increased road traffic and gas flaring. That, say experts, is understandable. “You can be ‘pro’ shopping malls, but not want a shopping mall in your backyard,” says Prof Brantley.

What about climate change?

The broader objection to fracking is that the more it is done, the more natural gas is produced and burnt, and the more greenhouse gases are released into the atmosphere, exacerbating global warming. Environmentalists say shale gas distracts attention and investment from renewables such as wind and solar that are crucial tools in fighting climate change. In the words of Caroline Lucas, the Green MP who was arrested during the Balcombe protests: “The evidence is clear that fracking undermines efforts to tackle the climate crisis.”
On the other hand, fracking’s promoters point to the fact that the increased use of gas can cut carbon emissions. Gas emits half the carbon dioxide per unit of energy of coal. As a result, US energy-related emissions of CO2 fell by 450m tonnes over the past five years as the power sector switched from coal to gas.

Nessun commento:

Posta un commento